Method of producing difluoromethyl ethers and esters and ethers and esters produced thereby

ABSTRACT

A process for producing difluoromethyl ethers and esters by reacting an ether or an acid with a cadmium, zinc or bismuth compound containing the CF 3  group and selected from the group consisting of Cd(CF 3 ) 2 , Zn(CF 3 ) 2 ,Bi(CF 3 ) 3 , CdHal(CF 3 ), ZnHal(CF 3 ), BiHal(CF 3 ) 2  and BiHal 2  (CF 3 ) in the presence of a Lewis acid.

BACKGROUND OF THE INVENTION

This invention relates to a process for producing ether and estercompounds which have a difluoromethyl group, and also to novel ethercompounds containing a difluoromethyl group which are obtainableaccording to the process of the invention.

Ether and ester compounds which have a difluoromethyl group (CF₂ H--),can be used in combination with surface-active compounds, e.g.phosphoric acid esters, for removing water from surfaces of objects. Incombination with agents which have a lubricating effect, they can beused as lubricants. Furthermore, difluoromethyl ethers, e.g. CHF₂ OC₆H₅, CHF₂ OCH₂ CF₃, CH₃ CH₂ OCF₂ H or CH₃ OCF₂ H, can be used assubstitutes for fluorochlorohydrocarbons.

Difluoromethyl esters are intermediate products and can be used assolvents.

The production by fluorination of corresponding dichloromethyl ethers isvery difficult due to the low reactivity of these compounds with respectto chlorine/fluorine exchange (in which a bond breakage may also takeplace on the oxygen atom).

The production of difluoromethyl phenyl ethers from chloroform,potassium fluoride and phenol, which is described by B. R. Langlois inTetrahedron Letters 32 (1991), pages 3691-3694, is successful, but onlywith a low yield.

The production of difluoromethyl ethers, e.g. from enfluorane orisofluorane, takes place by reacting the unstable starting compoundfluorosulphonyl difluoroacetate and alcohols, see Chen and Wu., J.Fluorine Chem. 44 (1989), pages 433 to 440. The authors mention that itis also possible to produce difluoromethyl ethers from difluoroaziridineand alcohol in glass ampoules. Due to the difficulty of supplyingaziridine, the application of this method is limited.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a useful processfor producing difluoromethyl ethers and esters.

It is also an object of the invention to provide new difluoromethylethers and esters.

These and other objects of the invention are achieved by providing aprocess for producing a compound corresponding to the formula (I)

    HF.sub.2 C--O--R (I)                                       (I)

wherein

R represents R¹, R¹ C(O), or (R¹ --R² --X);

R¹ represents linear or branched alkyl with 1 to 20 carbon atoms; linearor branched alkyl with 1 to 20 carbon atoms substituted by alkoxy,substituted alkoxy, halogen, CN or NO₂ ; aryl; or aryl substituted byhalogen, CN, NO₂, C1 to C6 alkyl, aryl or aryl substituted by at leastone aryl or C1 to C6 alkyl group which in turn may be substituted by oneor more substituents selected from the group consisting of halogen, CNand NO₂ ; or

R¹ and R² together form an alkylene chain with 2 to 20 carbon atoms, oran alkylene chain with 2 to 20 carbon atoms substituted by halogen, CN,NO₂, C1 to C6 alkyl or aryl, wherein said aryl and C1 to C6 alkylsubstituents in turn may be substituted with one or more substituentsselected from the group consisting of halogen, CN and NO₂, and

X represents halogen,

said process comprising reacting a compound corresponding to the formula(II)

    R.sup.2 --O--R.sup.1                                       (II)

wherein

R¹ has the meaning given above;

R² is hydrogen; alkyl with 1 to 20 carbon atoms; or alkyl with 1 to 20carbon atoms substituted by alkoxy, substituted alkoxy, halogen, CN, orNO₂ ; or

R¹ and R² together form an alkylene chain as defined above;

or if an ester bearing a CF₂ H--O group is to be produced, reacting acompound corresponding to the formula (III)

    R.sup.2 --O--C(O)R.sup.1                                   (III)

wherein

R² is hydrogen, and

R¹ has the above meaning,

in the presence of a Lewis acid with a CF₃ group-containing cadmium,zinc or bismuth compound selected from the group consisting of Cd(CF₃)₂,Zn(CF₃)₂, Bi(CF₃)₃, CdHal(CF₃), ZnHal(CF₃), BiHal(CF₃)₂ and BiHal₂(CF₃), wherein Hal is halide, which is dissolved in an organic solvent,and hydrolyzing the resulting reaction product.

In accordance with a further aspect of the invention, the objects areachieved by providing a compound corresponding to the formula

    HF.sub.2 C--(OCH.sub.2 CH.sub.2).sub.n --OY

wherein n is 2, 3 or 4, and Y represents an alkyl group containing 1 to4 carbon atoms, or to the formula

    HF.sub.2 C--O--CH.sub.2 CH.sub.2 Cl.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The process according to the invention for the production of compoundsof the general formula (I),

    HF.sub.2 C--O--R                                           (I)

wherein

R stands for R¹, (R¹ --R² --X) or for R¹ C(O) and R¹ is linear orbranched alkyl with 1 to 20 carbon atoms; linear or branched alkyl with1 to 20 carbon atoms substituted by alkoxy, substituted alkoxy, halogen,CN, NO₂ ; aryl; aryl substituted by halogen, CN, NO₂, C1 to C6 alkyl,aryl, or aryl substituted by one or more aryl or C1 to C6 alkyl groups,these aryl or C1 to C6 alkyl groups themselves being substituted by oneor more substituents selected from the group consisting of halogen, CNand NO₂ ; or

R¹ and R² together form an alkylene chain with 2 to 20 carbon atoms; analkylene chain with 2 to 20 carbon atoms substituted by halogen, CN,NO₂, C1 to C6 alkyl, aryl; or an alkylene chain with 2 to 20 carbonatoms substituted by aryl or C1 to C6 alkyl, these aryl or C1 to Cyalkyl groups themselves being substituted by one or more substituentsselected from the group consisting of halogen, CN and NO₂, and

X is halogen, in particular chloride or fluoride,

in that compounds of the general formula (II)

    R.sup.2 --O--R.sup.1                                       (II)

wherein

R¹ has the meaning defined above;

R² is hydrogen, alkyl with 1 to 20 carbon atoms, alkyl with 1 to 20carbon atoms optionally substituted by alkoxy, substituted alkoxy,halogen, CN, NO₂, or

R¹ and R² together form an alkylene chain as defined above;

or, in that in order to produce esters which bear the CF₂ H--O group,compounds of formula (III)

    R.sup.2 --O--C(O)R.sup.1                                   (III)

wherein R² is hydrogen and R¹ has the above meaning, are reacted in thepresence of a Lewis acid with a cadmium, zinc or bismuth compoundcontaining the CF₃ group and selected from the group consisting ofCd(CF₃)₂, Zn(CF₃)₂, Bi(CF₃)₃, CdHal(CF₃), ZnHal(CF₃), BiHal(CF₃)₂ andBiHal₂ (CF₃), wherein Hal is halide, preferably bromide or chloride,which is dissolved in a complexing, aprotic organic solvent, and theresulting reaction product is hydrolyzed.

The term "alkoxy" may, for example, denote C1 to C4 alkoxy. The term"substituted alkoxy" may, for example, denote C1 to C4 alkoxysubsitituted by one or more halogen atoms, particularly by fluorineatoms.

According to one embodiment, therefore, the R² group is cleaved off. Inthis case, R² is preferably C1-C5-alkyl, in particular methyl, ethyl ort-butyl.

R¹ is preferably C1-C6-alkyl or phenyl, or C1-C6-alkyl or phenylsubstituted by halogen, in particular one or more chlorine and/orfluorine atoms. For example, R¹ may be methyl, ethyl, phenyl,fluoromethyl, difluorochloromethyl, trifluoromethyl.2,2,2-trifluoroethyl, pentafluorophenyl.

According to another embodiment, R¹ in the compounds of the generalformula (I) stands for C1-C2-alkylene substituted by C1-C2-alkoxy, orfor A-O-B-O-C, wherein A and B stand for C1-C2-alkylene and C stands forC1-C4-alkyl. According to this variant, R¹ stands in particular foroligomeric radicals CH₂ CH₂ --(OCH₂ CH₂)_(n) --OY with n=1 to 4, e.g.CH₂ CH₂ --O--CH₂ CH₂ --OY, wherein Y stands for methyl, ethyl, propyland butyl.

According to a further embodiment, R¹ and R² form an alkylene chain with2 to 4 carbon atoms or an alkylene chain with 2 to 4 carbon atomssubstituted by one or more halogen atoms, in particular chlorine and/orfluorine.

A wide variety of Lewis acids can be used. Suitable examples includehalogen compounds of elements of groups III and IV of the periodictable. Halogen compounds of elements of group III, e.g. boron,aluminium, indium and gallium, in particular chlorides or fluorides, areespecially suitable. Halogen compounds of boron and indium are veryespecially suitable. Boron trichloride, indium trichloride, borontrifluoride and adducts of boron trifluoride, in particular withnitriles, such as acetonitrile, ethers such as dimethyl ether, diethylether, methyl-t-butyl ether, are very highly suitable. Boric acid estersare also suitable.

The zinc, bismuth or cadmium compound is used dissolved in an organicsolvent. It is present in the solvent in the form of an adduct. Inaddition to bromide and chloride, which are preferred, Hal may alsostand for iodide.

Various methods known to persons skilled in the art may be used forproducing this solution, as will be explained with reference to cadmiumcompounds. Zinc and bismuth compounds are treated analogously.

For example, cadmium compounds of the general formula (CF₃)₂ Cd.D,wherein the symbol D represents an organic Lewis base, may be dissolvedin a corresponding solution. In these compounds, the cadmium compound isalready present as an adduct. Compounds of this type are known, cf. H.Lange, D. Naumann, J. Fluor. Chem., 26 (1984), pages 1 to 18. In theformula, the symbol "D" represents 2 molecules of those Lewis baseswhich can only provide one pair of electrons for coordination, or 1molecule of those Lewis bases which can provide two or more pairs ofelectrons for coordination. Examples of the former include nitriles,such as acetonitrile, cyclic amines, such as pyridine, and examples ofthe latter include ethers, for example oligomeric ethers, preferably ofthe formula CH₃ --(OCH₂ CH₂)_(n) --OCH₃ with n=1 to 4, such as ethyleneglycol dimethyl ether ("glyme"), diethylene glycol dimethyl ether("diglyme"), N,N,N',N'-tetramethyl ethylene diamine ("TMED"). Thesecadmium compounds are insensitive to oxygen and are crystallinesubstances which are stable at room temperature. As stated in theaforementioned literature source, they may be produced from dimethylcadmium, diethyl cadmium, trifluoromethyl iodide and the correspondingLewis base with subsequent evaporation of volatile compounds. Theproduction of the required dialkyl cadmium compounds is described in"Methoden der organischen Chemie (Houben-Weyl), 4th edition (1973),volume XIII/2a, pages 867 and 868". The resulting crystallinetrifluoromethyl cadmium compounds may then be dissolved in a complexingsolvent, as already stated above. This embodiment for producing thesolution is preferred.

In accordance with another embodiment, this solution of thetrifluoromethyl compound can be produced by producing thetrifluoromethyl cadmium compound in a solution which contains complexingsolvent, and using it in situ in the process according to the invention,as described in the literature source quoted.

It will be apparent to a person skilled in the art that the complexingsolvent stabilizes the trifluoromethyl cadmium compound. It isadvantageous if during the reaction there is always a quantity ofcomplexing solvent which is sufficient for stabilization in the reactionmixture. However, it is also clear to a person skilled in the art thatthe solvent need not consist of this complexing solvent. If desired,non-complexing, inert organic solvents which are miscible with thecomplexing solvent may also be present in the reaction mixture. Theseinclude, for example, halogenated hydrocarbons such as chloroform,hydrocarbons such as pentane, hexane or petroleum ether fractions, oraromatic solvents such as toluene. The content of such non-complexingsolvents in the solvent mixture may be up to 100% by weight, for examplebetween 0 and 90% by weight.

Aprotic, polar organic Lewis base compounds which may provide 1, 2 ormore pairs of electrons for coordinate bonding are used as complexingsolvents. Examples of these include aliphatic ethers, e.g. dialkylethers such as diethyl ether, cycloaliphatic ethers, for exampletetrahydrofuran, oligomeric aliphatic ethers, for example the "glyme"and "diglyme" mentioned above, nitriles, for example acetonitrile,oligomeric tetraalkyl-substituted diamines or polyamines, for exampletetramethyl ethylene diamine, mixed aliphatic-aromatic ethers (e.g.anisole), lactams, formamides, carboxylic acid amides, and sulfones.

If it is desired to use ether compounds as solvents, it is advantageousto use as the solvent, the ether starting compound of Formula (II) whichis also used as a reactant.

The production of Zn(CF₃)₂.2D is described by H. Lange and D. Naumann inJ. Fluorine Chem. 26 (1984), pages 435 and 444. According to thisarticle, CF₃ I is reacted with dialkyl zinc compounds, e.g. dimethylzinc or diethyl zinc, in the presence of a Lewis base, e.g. glyme ordiglyme, pyridine, forming Zn(CF₃)₂.2D.

The production of Bi(CF₃)₃ is described by D. Naumann and W. Tyrra in J.Organomet. Chem. 334 (1987), pages 323 ff.

The production of trifluoromethyl-zinc, trifluoro-methyl-cadmium andtrifluoromethyl-bismuth halides is described in published EuropeanPatent Application No. EP 291,860. In this process, zinc, cadmium orbismuth in metallic form is reacted in a complexing solvent, for exampleacetonitrile, with CF₃ Hal, e.g. CF₃ Br. The reaction may be promoted bycatalysts, e.g. iodine, and also by ultrasound.

The reaction of the zinc, bismuth or cadmium compound with therespective starting compound used takes place at a temperature of -78°C. to +20° C. The molar ratio of the starting compound (II) to thetrifluoromethyl cadmium compound used may be in the range of about 1:1to 20:1. It is preferably between about 2:1 and 4:1. The use of (II) asa solvent is advantageous.

Advantagously, the process is carried out by initially producing amixture of the trifluoromethyl metal compound and the starting compoundin the organic solvent and then adding the Lewis acid. The molar ratioof metal compound to Lewis acid is between about 1:1.5 and 1:5.Preferably it lies between about 1:1.5 and 1:3.

The Lewis acid, for example a boron trihalide adduct or indium halidesuch as indium trichloride, may be added as a solid. It is of coursealso possible to add a slurry or solution of the Lewis acid, for examplein the solvent used.

After addition, an exothermic reaction then begins. If desired, an inertgas such as nitrogen may be passed over the reaction mixture, Thereaction mixture also may be left for some time, for example up toseveral hours, in order to complete the reaction. Then a molar quantityof a protic compound, for example an acid, an alcohol or,advantageously, water, is added to the reaction mixture. To work up themixture, volatile constituents may be separated by fractionaldistillation. In this manner, the desired difluoromethyl ether compoundof formula (I) can be isolated.

Without being bound to any theory of the reaction, it is believed thatthe bond between the oxygen atom and one of the two organic radicals,for example R², is broken and this organic radical is finally replacedby the CF₂ H group. If a halide is used as the Lewis acid, acorresponding halide of this cleaved-off organic radical R² forms in thereaction mixture. In contrast, if a compound of the general formula (II)in which R¹ and R² together form a (bridging) alkylene chain is used asthe starting compound, a compound of the general formula HF₂ C--O--R¹ R²X is produced if for example AlX₃, InX₃ or BX₃ with X=Cl, Br has beenused as the Lewis acid.

The process of the invention is suitable for producing compounds of thegeneral formula (I) in which R has the meaning given above. The processof the invention is particularly suitable for producing compounds offormula (I) in which R is CH₃, C₂ H₅, CH₂ CF₃, (CH₂)₃ CH₃, (CH₂)₄ Cl, C₆H₅, C₆ F₅ or CH₂ CH₂ --O--CH₂ CH₂ --OCH₃.

The invention also relates to novel compounds, which can be used aslubricants and can be obtained according to the process of theinvention, corresponding to the formula HF₂ C--(OCH₂ CH₂)_(n) --OYwherein n=2 to 4 and Y=C1-C4-alkyl, preferably for compounds of thegeneral formula (IV),

    HF.sub.2 C--OCH.sub.2 CH.sub.2 --OCH.sub.2 CH.sub.2 --OY   (IV)

wherein Y represents methyl, ethyl, propyl or butyl. The compound HF₂C--O--CH₂ CH₂ Cl is also novel.

The compounds obtainable according to the process of the invention canbe used for the purposes mentioned a the beginning of this specificationfor which they are usually used, e.g. as intermediate products inchemical synthesis, as lubricants, coolants etc.

The following examples serve to illustrate the invention in furtherdetail without restricting its scope. Example 1

Production of HF₂ C--O--(CH₂)₄ Cl.

The adduct of diethylene glycol dimethyl ether and bistrifluoromethylcadmium, Cd(CF₃)₂ diglyme, was used as the trifluoromethyl cadmiumcompound. This compound was produced from trifluoromethyl iodide,diglyme and dimethyl cadmium in accordance with the method in H. Lange,D. Naumann, J. Fluor. Chem. 26 (1984), page 13.

7.6 g of (19.76 mmol) Cd(CF₃)₂ diglyme were dissolved in 25 mltetrahydrofuran (THF) under an inert gas atmosphere. 2.9 g (13.11 mmol)of indium trichloride were added to the solution, which was stirred bymeans of a magnetic stirrer, at room temperature. An exothermic reactionbegan, and a white solid was precipitated. The reaction mixture wasstirred for a further 24 hours, during which time the suspension becameincreasingly viscous. 10 g of water were then added to the reactionmixture. The reaction mixture was worked up by evaporating the solventtetrahydrofuran and readily volatile constituents at room temperatureunder a high vacuum. The residue was then heated to 50° C. and subjectedto fractional distillation under a high vacuum. Characterization bynuclear resonance spectroscopy and mass spectroscopy yielded thefollowing data:

HCF₂ O(CH₂)₄ Cl:

¹ H n.m.r.: (p.p.m)/CDCl₃ : 6.12 (t, ² J_(F-H) 75.2 Hz, HCF₂), 3.56 (m,CH²), 1.66 (m, CH₂), 1.55 (m, CH₂), 3.50 (m, CH2).

¹⁹ F n.m.r.: (p.p.m.)/CDCl₃ : -84.35 (d ² J_(F-H) 75.2 Hz,

¹³ C n.m.r.: (p.p.m.)/CDCl₃ : 116.06 (t, ¹ J_(F-C) 260.1 Hz, CF₂ HO--),62.35 (t ³ J_(F-C) 5.1 Hz CF₂ HOCH₂ --), 26.05 (--CH₂ --), 29.52 (--CH₂--), 44.95 (--CH₂ Cl).

m.s. (70 dV: ³⁵ Cl isotope; m/e): 158 (4.0%, M+).

CF₂ HO(CH₂)₂ OCH₃ :

¹ H n.m.r.: (CF₂ HO) (p.p.m.)/CDCl₃ : 6.20 (t ² J_(F-H) 75.2 Hz).

¹⁹ F m.m.r.: (CF₂ HO) (p.p.m.)/CDCl₃ : -84.63 (d, ² J_(F-H) 74.6 Hz).

m.s. (70 eV: m>80; m/e): 170 (10.1%, M+) .

Example 2:

Production of difluoromethyl-2,2,2-trifluoroethyl ether.

4.77 g of Zn(CF₃)Br.2CH₃ CN (16.09 mmol), produced as described inpublished European Patent Application No. EP 291 860, were suspended in40 ml CH₂ Cl₂. 2 g of BF₃.CH₃ CN (18.37 mmol) were added to thissuspension at a temperature of -78° C. Then 2.5 ml of trifluoroethanol(34.72 mmol) were added. The reaction mixture was stirred for one hourat -78° C, then heated to -55° C. and heated to room temperature withinabout 3 hours. During this time, Zn(CF₃)Br.2CH₃ CN was completelyreacted. The reaction mixture was worked up by distillation undervacuum. The fraction obtained at 0° C. contained in addition todifluoromethyl-2,2,2-trifluoroethyl ether an additional compound, whichmay be bis-2,2,2-trifluoroethyl ether (¹⁹ F-NMR: δ-74.63 ppm; ² J(¹⁹ F-¹H)=8.9 Hz) (integration ratio: 1.3:1). The second fraction (0° C. to RT)contained only traces of difluoromethyl-2,2,2-trifluoroethyl ether,while presumably CF₃ CH₂ OCH₂ CF₃ was present as the main product(integration ratio: 1:15).

¹⁹ F-NMR data of CHF₂ OCH₂ CF₃ :

(CH₂ Cl₂, 20° C.)

δ(CF₃) -75.36 ppm, tt

³ J(¹⁹ F-¹ H)=8.3 Hz

⁵ J(¹⁹ F-¹⁹ F)=2.5 Hz

δ(CHF₂) -86.74 ppm, dq

² J(¹⁹ F-¹ H)=72.5 Hz

⁵ J(¹⁹ F-¹⁹ F)=2.5 Hz.

Example 3

Production of difluoromethyl phenyl ether.

15.97 g of Zn(CF₃)Br.2CH₃ CN (53.87 mmol) were suspended in 60 ml CH₂Cl₂. 6 g of BF₃.CH₃ CN (55.12 mmol) were added to the suspension, withstirring, at -78° C. Then 10 g phenol (106.26 mmol) were added. Thereaction mixture was stirred for one hour at -78° C., then heated to-55° C. and warmed to room temperature over a period of 3 hours.Zn(CF₃)Br.2CH₃ CN could no longer be detected by ¹⁹ F-NMR spectroscopy.The reaction mixture was worked up by vacuum distillation. At 0° C., themajority of the solvent had been removed from the reaction mixture.Distillation in a stream of hot air yielded a reddish-brown coloredsolution which contained phenol, acetonitrile, dichloromethane,presumably C₆ H₅ OCF₂ OC₆ H₅ (¹⁹ F-NMR: δ-76.39 ppm, ¹ J(¹⁹ F-¹³C)=290.4 Hz, Δδ 0.1282 ppm) and BF₃ adducts in addition todifluoromethyl phenyl ether. After the addition of NaF, the mixture wasfreed of residual solvent in a vacuum (170-210 mbar). The mixture wasworked up further by renewed distillation in a stream of hot air, whichmeant that a high enrichment of difluoromethyl phenyl ether wasachieved.

¹⁹ F-NMR data of CHF₂ OC₆ F₅

(CDCl₃, 20° C.)

δ(CHF₂ ) -81.23 ppm, d

² J(¹⁹ F-¹ H)=73.8 Hz

¹ J(¹⁹ F-¹³ C)=258.9 Hz; Δδ0.1247 ppm

¹ H-NMR data of CHF₂ OC₆ H₅

(CDCl₃, 20° C.)

δ(CHF₂) 6.50 ppm, t

² J(¹⁹ F-¹ H)=74.0 Hz

δ(aromatic) 6.85; 7.12; 7.35 ppm

Example 4:

Production of chlorodifluoroacetic acid difluoromethyl ester.

1.07 g of Zn(CF₃)Br.2CH₃ CN (3.61 mmol) were suspended in 10 ml CH₂ C₂,and 0.4 g BF₃.CH₃ CN (3.67 mmol) were added thereto with stirring at-65° C. Then approximately 1.04 g of chlorodifluoroacetic acid(approximately 7.97 mmol) were added. After 30 minutes, the cold bathwas removed and the mixture was heated to room temperature withstirring. The Zn compound used could no longer be detected.

¹⁹ F-NMR data of CF₂ ClCOOCF₂ H:

(CH₂ Cl₂, 20° C.)

δ(CF₂ Cl) -65.91 ppm

δ(CF₂ H) -91.74 ppm, d

² J(¹⁹ F-¹ H)=68.7 Hz.

Example 5

Production of trifluoroacetic acid difluoromethyl ester.

1.12 g of Zn(CF₃)Br.2CH₃ CN (3.78 mmol) were suspended in 10 ml CH₂ Cl₂,and 0.4 g BF₃.CH₃ CN (3.67 mmol) were added thereto at -65° C. Then 0.7ml of trifluoroacetic acid (9.09 mmol) were added, with stirring. After30 minutes, the cold bath was removed, and the mixture was heated toroom temperature with stirring.

¹⁹ F-NMR data of CF₃ COOCF₂ H:

(CH₂ Cl₂, 20° C.)

δ(CF₃) -76.1 ppm

δ(CF₂ H) -91.93 ppm, d

² J(¹⁹ F-¹ H)=64.8 Hz.

Example 6

Production of pentafluorobenzoic acid difluoromethyl ester.

3 g of Zn(CF₃)Br.2CH₃ CN (10.12 mmol) were suspended in 20 ml CH₂ C₂.The mixture was cooled to -60° C., and 1.1 g of BF₃.CH₃ CN (10.10 mmol)were added thereto with stirring. Then 4.3 g of pentafluorobenzoic acid(20.27 mmol) were added, The reaction mixture was left at thistemperature for 1 hour before the cold bath was removed. It was warmedto room temperature with stirring. The Zn(CF₃)Br.2CH₃ CN was completelyreacted.

¹⁹ F-NMR data of C₆ F₅ COOCF₂ H:

(CH₂ Cl₂, 20° C.)

δ(CF₂ H) -92.54 ppm, d

² J(¹⁹ F-¹ H)=70.1 Hz

δ(C₆ F₅, o) -136.87 ppm

δ(C₆ F₅, p) -145.66 ppm

δ(C₆ F₅, m) -160.70 ppm.

The foregoing description and examples have been set forth merely toillustrate the invention and are not intended to be limiting. Sincemodifications of the described embodiments incorporating the spirit andsubstance of the invention may occur to persons skilled in the art, thescope of the invention should be construed to include all variationsfalling within the ambit of the appended claims and equivalents thereof.

What is claimed is:
 1. A process for producing a compound correspondingto the formula (I)

    HF.sub.2 C--O--R                                           (I)

wherein R represents R¹, R¹ C(O), or (R¹ --R² --X); R¹ represents linearor branched alkyl with 1 to 20 carbon atoms; linear or branched alkylwith 1 to 20 carbon atoms substituted by alkoxy, substituted alkoxy,halogen, CN or NO₂ ; aryl; or aryl substituted by halogen, CN, NO₂, C1to C6 alkyl, aryl or aryl substituted by at least one aryl group or C1to C6 alkyl group or aryl group or C1 to C6 alkyl group substituted byone or more substituents selected from the group consisting of halogen,CN and NO₂ ; or R¹ and R² together form an alkylene chain with 2 to 20carbon atoms, or an alkylene chain with 2 to 20 carbon atoms substitutedby halogen, CN, NO₂, C1 to C6 alkyl or aryl, or aryl and or C1 to C6alkyl substituted with one or more substituents selected from the groupconsisting of halogen, CN and NO₂, and X represents halogen,said processcomprising reacting a compound corresponding to the formula (II)

    R.sup.2 --O--R.sup.1                                       (II)

wherein R¹ has the meaning given above; R² is hydrogen; alkyl with 1 to20 carbon atoms; or alkyl with 1 to 20 carbon atoms substituted byalkoxy, substituted alkoxy, halogen, CN, or NO₂ ; or R¹ and R² togetherform an alkylene chain as defined above;or if an ester bearing a CF₂H--O group is to be produced, reacting a compound corresponding to theformula (III)

    R.sup.2 --O--C(O)R.sup.1                                   (III)

wherein R² is hydrogen, and R¹ has the above meaning,in the presence ofa Lewis acid with a CF₃ group-containing cadmium, zinc or bismuthcompound selected from the group consisting of Cd(CF₃)₂, Zn(CF₃)₂,Bi(CF₃)₃, CdHal(CF₃), ZnHal (CF₃), BiHal(CF₃)₂ and BiHal₂ (CF₃), whereinHal is halide, which is dissolved in an organic solvent, and hydrolyzingthe resulting reaction product.
 2. A process according to claim 1,wherein X represents chlorine or fluorine.
 3. A process according toclaim 1, wherein Hal represents bromide or chloride.
 4. A processaccording to claim 1, wherein said Lewis acid comprises a halogencompound of an element of Group III of the periodic table.
 5. A processaccording to claim 4, wherein said Lewis acid is a chloride or fluorideof an element of Group III of the periodic table.
 6. A process accordingto claim 4, wherein said Lewis acid is a halogen compound of boron orindium.
 7. A process according to claim 6, wherein said Lewis acid isselected from the group consisting of boron trifluoride, adducts ofboron trifluoride with acetonitrile, dimethyl ether, diethyl ether ormethyl-t-butyl ether, boron trichloride and indium trichloride.
 8. Aprocess according to claim 1, wherein said solvent is selected from thegroup consisting of aliphatic ethers, cycloaliphatic ethers, oligomericaliphatic ethers, nitriles, lactams, formamides, carboxylic acid amides,sulfones, halogenated hydrocarbons, alcohols and optionally substitutedaromatic hydrocarbons,
 9. A process according to claim 8, wherein saidsolvent is an oligomeric ether corresponding to the formula

    CH.sub.3 --(OCH.sub.2 CH.sub.2).sub.n --OCH.sub.3,

wherein n is 1 to
 4. 10. A process according to claim 1, wherein thereaction of the compound of formula (II) to form a compound of formula(I) is carried out at a temperature of -78° C. to +20° C.
 11. A processaccording to claim 1, wherein the molar ratio of the compound of formula(II) to the zinc, bismuth or cadmium compound is between about 1:1 and20:1.
 12. A process according to claim 11, wherein the molar ratio ofthe compound of formula (II) to the zinc bismuth or cadmium compound isbetween 2:1 and 4:1.
 13. A process according to claim 1, wherein themolar ratio of Lewis acid to zinc, bismuth or cadmium compound isbetween about 1.5:1 and 5:1.
 14. A process according to claim 13,wherein the molar ratio of Lewis acid to zinc bismuth or cadmiumcompound is between about 1.5:1 and 3:1.
 15. A process according toclaim 1, wherein R² represents an alkyl group containing 1 to 5 carbonatoms.
 16. A process according to claim 15, wherein R² represents amethyl, ethyl or t-butyl group.
 17. A process according to claim 1,wherein R¹ represents an alkyl group containing 1 to 6 carbon atoms, andalkyl group containing 1 to 6 carbon atoms substituted by halogen, aphenyl group, or a phenyl group substituted by halogen.
 18. Aprocess-according to claim 1, wherein R¹ and R² represent an alkylenechain with 2 to 4 carbon atoms or an alkylene chain with 2 to 4 carbonatoms substituted by halogen.